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IK3301

Rev. 01

Electrical Description

The standard external components for standard load are shown in Figure 4.

1. Multi-output Generation(-8V & 5V & 15V)

IK3301 consists of CMOS step-down, step-up, and Voltage-inverting switching regulator, which produces

5V, 15V, and -8V. This device contains an internal temperature compensated bandgap reference,

comparator, duty cycle controlled oscillator with cycle-cycle current limit circuit, and high current

output switch with logic gates. Three outputs of 5V, 15V, and -8V are adjustable through two

external feedback resistors with 2% reference voltage accuracy. The power efficiency depends on

the value and the efficiency of external components, the load current and the target ripple voltage.

The minimum efficiency of the 5V voltage generator is 80% with the reference circuit shown in

Figure 4. The maximum load current of 5V of the reference circuit is 300mA, the maximum ripple

voltage is 20mV. To save external components, internal Pch and Nch Power MOS FET are used

to generate -8V and 15V. The 5V Pch Power MOS FET is used as external component because of

high peak current and package power dissipation.

2. Internal BG Reference

IK3301 generates three outputs which are determined by the internal bandgap reference voltage and the

ratio of the feedback resistors. Therefore, the output voltages of 15V, 5V, and -8V are also

insensitive of the temperature and power supply variations.

3. Internal Oscillator

IK3301 has an internal oscillator which charges and discharges the internal timing capacitor using current

sourcing and sinking between an upper and lower predetermined threshold voltage. The upper

threshold voltage is 1.8V and the lower threshold voltage is 0.8V. The charging current and

discharging current ratio is one to six which will vary depending on running frequency. The

oscillator frequency is around 500KHz which is determined by the chosen internal capacitor value

and charging & discharging current and oscillator amplitude.

Internal Oscillator